Search found 100 matches
- Sun Mar 15, 2020 4:42 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: exam order
- Replies: 2
- Views: 226
Re: exam order
k=Ae^{-Ea/RT} is the equation and doesn't have anything that is affected by order.
- Sun Mar 15, 2020 4:40 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: catalyst
- Replies: 4
- Views: 335
Re: catalyst
It is present at the beginning and reappears at the end as opposed to an intermediate which forms and disappears during the reaction
- Sun Mar 15, 2020 4:38 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Arrhenius eq
- Replies: 6
- Views: 406
Re: Arrhenius eq
Also when you are looking at activation energy
- Sun Mar 15, 2020 4:37 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: heterogeneous vs homogeneous catalysts
- Replies: 2
- Views: 209
Re: heterogeneous vs homogeneous catalysts
I think it's helpful in the future when you are working in the lab and you need to choose a catalyst.
- Sat Mar 07, 2020 11:11 pm
- Forum: Second Order Reactions
- Topic: Termolecular
- Replies: 43
- Views: 2199
Re: Termolecular
Its not commonly seen though because the chances of 3 molecules hitting simultaneously is super low which is why we don't cover third order
- Sat Mar 07, 2020 11:11 pm
- Forum: Second Order Reactions
- Topic: Half-life of Second-Order
- Replies: 4
- Views: 484
Re: Half-life of Second-Order
Second order half life is 1/k[A]0 and it is used.
- Sat Mar 07, 2020 11:03 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: activation energy/ energy barrier
- Replies: 6
- Views: 433
Re: activation energy/ energy barrier
Activation energy is the amount of energy needed before a reaction could proceed. There is a numerical value and it's important because a larger activation energy tends to have a slower reaction. Also this is important when it comes to enzymes
- Sat Mar 07, 2020 11:00 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: linear plots
- Replies: 7
- Views: 527
Re: linear plots
I think he could give us a question with a plot and ask us what order the reaction is.
- Sat Mar 07, 2020 10:54 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Rate Determining Steps in a series of Elementary Steps
- Replies: 2
- Views: 205
Re: Rate Determining Steps in a series of Elementary Steps
Dr. Lavelle said he would show us an example Monday but yeah since there is a buildup of B the B reverts back to A so thus we can treat it as if the step is in equilibrium.
- Sun Mar 01, 2020 1:03 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Order of reaction
- Replies: 3
- Views: 643
Re: Order of reaction
I found this on a website and it feels like an apt summary
Zero order: No effect
First order: Rate doubles when reactant doubled
Second order: Rate quadruples when reactant doubled
Third order: Rate increases eightfold when reactant doubled.
Zero order: No effect
First order: Rate doubles when reactant doubled
Second order: Rate quadruples when reactant doubled
Third order: Rate increases eightfold when reactant doubled.
- Sun Mar 01, 2020 12:58 pm
- Forum: General Rate Laws
- Topic: Unique Rate Applications
- Replies: 2
- Views: 256
Re: Unique Rate Applications
I think they might ask you to try to find the order of reactions if they give you experimental data.
- Sun Mar 01, 2020 12:54 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: determine n
- Replies: 16
- Views: 1368
Re: determine n
If you're talking about kinetics n is the order of the reactant.
- Sun Mar 01, 2020 12:52 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Units k
- Replies: 3
- Views: 612
Re: Units k
you're trying to get a rate of M/s so if you set up the rate calculations you can see that for first order you get k times M. Thus k would need units of s^-1 to obtain M/s. So you can calculate the units of k like this for each order. Its easier to be able to calculate then remembering.
- Sun Mar 01, 2020 12:46 pm
- Forum: General Rate Laws
- Topic: Reaction Rates
- Replies: 5
- Views: 363
Re: Reaction Rates
It's all about how the rates are calculated for products its d[P]/dt while for reactants its -d[R]/dt. Its just easier to think about rates in terms of being positive.
- Sat Feb 22, 2020 4:40 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: max potential in Galvanic Cell
- Replies: 4
- Views: 280
Re: max potential in Galvanic Cell
I think that this was when Professor Lavelle was talking about the switch being opened
- Sat Feb 22, 2020 4:39 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridge
- Replies: 10
- Views: 598
Re: Salt Bridge
It lets ions flow freely and thus the reaction won't be influenced by all of the free ions.
- Sat Feb 22, 2020 4:34 pm
- Forum: Balancing Redox Reactions
- Topic: Homework 6K.5
- Replies: 2
- Views: 192
Re: Homework 6K.5
Remember OIL RIG or LEO says GER. Look at oxidation states of elements. When oxidation states get more positive they are losing electrons and thus being oxidized.
- Sat Feb 22, 2020 3:44 pm
- Forum: Balancing Redox Reactions
- Topic: 6K3, part d
- Replies: 2
- Views: 117
Re: 6K3, part d
If you look at it, it doesn't make sense for it to go from Cl2 to Cl2. Even if I didn't know its a typo, I would change the products because it feels wrong to have the reactant also be a product. Or at the very least ask about it if its on an exam.
- Sat Feb 22, 2020 3:39 pm
- Forum: Balancing Redox Reactions
- Topic: Finding moles of the reaction
- Replies: 4
- Views: 477
Re: Finding moles of the reaction
The n stands for the number of moles of electrons. Look at the oxidation states of the reactions and figure out how many moles of electrons are exchanged.
- Sun Feb 16, 2020 9:37 pm
- Forum: Van't Hoff Equation
- Topic: Variable Explanations
- Replies: 3
- Views: 179
Re: Variable Explanations
K2 is K at one temperature while K2 is K at another temperature. K means equilibrium constant. Delta H is enthalpy and delta s is entropy. R is the gas constant and T is temperature.
- Sun Feb 16, 2020 9:35 pm
- Forum: Van't Hoff Equation
- Topic: Temperature and K
- Replies: 2
- Views: 190
Re: Temperature and K
I think it’s harder to relate K to temperature since the equation compares the two Ks as a ratio of ln(K2/k1)
- Sun Feb 16, 2020 9:32 pm
- Forum: Van't Hoff Equation
- Topic: K in Van't Hoff
- Replies: 3
- Views: 229
Re: K in Van't Hoff
The Van’t Hoff equation is to compare Ks at different temperatures. Thus if you know K at one temperature you can find K at another temperature as long as you know delta H, delta S, and R
- Sun Feb 16, 2020 9:30 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Van't Hoff Equation
- Replies: 2
- Views: 156
Re: Van't Hoff Equation
I think that there are certain caveats, but the assumption is that the two temperatures wouldn’t be different enough to change the delta S
- Sun Feb 16, 2020 9:26 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: K equation with Gibbs free energy
- Replies: 3
- Views: 167
Re: K equation with Gibbs free energy
I think the problems usually use -G=RTlnK more, but you would probably use G=G*+RTlnK to compare G at non standard conditions
- Sun Feb 09, 2020 8:54 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Types of reaction & Equations
- Replies: 3
- Views: 128
Re: Types of reaction & Equations
Try writing down the tidbits given to you in problem and looking for equations that have the variables that you know. Sorry if this isn't helpful
- Sun Feb 09, 2020 8:48 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: How to find the W?
- Replies: 3
- Views: 130
Re: How to find the W?
W= #microstates ^ # of particles. There are 12 micro states and 6.02*10^23 is the amount of particles in one mole
- Sun Feb 09, 2020 8:44 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Degrees of Change in Entropy
- Replies: 5
- Views: 181
Re: Degrees of Change in Entropy
When there is a degrees symbol and it's not attached to C, it means standard so under standard conditions.
- Sun Feb 09, 2020 8:41 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Finding whether exothermic or Endothermic
- Replies: 4
- Views: 153
Re: Finding whether exothermic or Endothermic
You can also tell by the reactions. For example a solid going to liquids or gas. You need heat to provide energy to break up intermolecular forces and thus the reaction is endothermic. Try thinking about the forces and bonds and how you need energy to break them
- Sun Feb 09, 2020 8:38 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: 4H.9
- Replies: 2
- Views: 171
Re: 4H.9
I think it has to do with the fact that it is a monatomic gas compared to b and c which are diatomic gases. Because each particle is not bound to another, the monatomic gas probably has more available positions and entropy.
- Sun Feb 02, 2020 1:33 pm
- Forum: Phase Changes & Related Calculations
- Topic: Homework 4A.9
- Replies: 3
- Views: 141
Re: Homework 4A.9
The negative sign is there to help signify the relationship between the two temperatures and it doesn't really matter because you just want to have the right amounts of negatives on both sides.
- Sun Feb 02, 2020 1:30 pm
- Forum: Phase Changes & Related Calculations
- Topic: 4C.13
- Replies: 2
- Views: 160
Re: 4C.13
Whenever there is phase change you add the heat of fusion/vaporization to the amount of energy it takes to raise the substance a certain amount of degrees. If you look at the phase change curve you can see it's flat then it starts increasing in temperature. The flat area is the phase change.
- Sun Feb 02, 2020 1:22 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: kinetics
- Replies: 8
- Views: 184
Re: kinetics
We haven't gone over kinetics but is more about rate while thermodynamics is more like the transference of energy.
- Sun Feb 02, 2020 1:19 pm
- Forum: Calculating Work of Expansion
- Topic: Gas constant
- Replies: 5
- Views: 247
Re: Gas constant
Where are you getting 3.314?
- Sun Feb 02, 2020 1:18 pm
- Forum: Calculating Work of Expansion
- Topic: L atm and J
- Replies: 3
- Views: 1010
Re: L atm and J
when you use -p delta v you get units of 1 L atm so you use 1 L atm = 101.33 J to get to J
- Sun Jan 26, 2020 9:34 pm
- Forum: Phase Changes & Related Calculations
- Topic: Standard reaction enthalpy vs. Standard enthalpy of formation
- Replies: 2
- Views: 82
Re: Standard reaction enthalpy vs. Standard enthalpy of formation
Standard enthalpy of reaction can be any type of reaction but standard enthalpy of formation is specifically forming one mole of a compound using elements in standard states.
- Sun Jan 26, 2020 9:32 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase changes
- Replies: 8
- Views: 168
Re: Phase changes
standard enthalpy changes will be in a certain phase and sometimes you have to add enthalpy of phase changes to calculate enthalpy of reactions.
- Sun Jan 26, 2020 9:18 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard enthalpy of formation of O2
- Replies: 4
- Views: 211
Re: Standard enthalpy of formation of O2
02 is already the most stable form of oxygen and so if you look at 02 to 02 the enthalpy of formation would be enthalpy of 02-enthalpy of 02 equaling 0
- Sun Jan 26, 2020 9:14 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Meaning of State Function
- Replies: 8
- Views: 205
Re: Meaning of State Function
All you care about is final and initial so enthalpy of product minus enthalpy of reactants
- Sun Jan 26, 2020 9:12 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpies
- Replies: 3
- Views: 122
Re: Bond Enthalpies
There are tables where all of the enthalpies have been found.
- Sun Jan 19, 2020 5:43 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: 5J.5
- Replies: 2
- Views: 88
Re: 5J.5
When volume decreases, the reaction favors the side with less moles of gas.
- Sun Jan 19, 2020 5:42 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: pKa
- Replies: 13
- Views: 450
Re: pKa
Lower pKa means a less negative Ka which means that there is a high amount of dissociation and thus a stronger acid.
- Sun Jan 19, 2020 5:39 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5I 33
- Replies: 2
- Views: 93
Re: 5I 33
It's not a part of the problem. It's most likely put there to trick you. You don't need to know about the reactants since it is a solid and thus wouldn't go into calculations. Since you know the mass of CO2 then you know molarity of CO2 and molarity of NH3. CO2 would be equivalent to X and NH3 would...
- Sun Jan 19, 2020 5:34 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Acids/Bases and Chemical Equilibrium
- Replies: 2
- Views: 114
Re: Acids/Bases and Chemical Equilibrium
Acids/Bases usually require a lot of ICE tables since weak acids/bases don't dissociate completely
- Sun Jan 19, 2020 5:32 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: temperature change in reactions
- Replies: 11
- Views: 371
Re: temperature change in reactions
If a reaction is endothermic than it requires heat to get to the products so adding heat is favoring the products. If a reaction is exothermic, that is saying the same thing as the reverse reaction is endothermic so increasing temperature favors the reactants.
- Sun Jan 12, 2020 12:25 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: When to do ice tables [ENDORSED]
- Replies: 4
- Views: 246
Re: When to do ice tables [ENDORSED]
A hint to do an ICE might be when you get only a few concentrations and you get K
- Sun Jan 12, 2020 12:23 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: States of matter [ENDORSED]
- Replies: 4
- Views: 143
Re: States of matter [ENDORSED]
Solids and liquids have a basically constant concentration so it won't change K because it would just cancel out if you write it out.
- Sun Jan 12, 2020 12:21 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Meaning of K [ENDORSED]
- Replies: 4
- Views: 184
Re: Meaning of K [ENDORSED]
K is the ratio of products and reactants. Things like increasing temperature and adding a catalyst speed up the rates.
- Sun Jan 12, 2020 12:19 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Calculating K
- Replies: 5
- Views: 158
Re: Calculating K
If you included it since the concentration doesn't change, the liquid and solid would just cancel out.
- Sun Jan 12, 2020 12:15 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc vs. Kp [ENDORSED]
- Replies: 4
- Views: 277
Re: Kc vs. Kp [ENDORSED]
Yes when we see gas we assume Kp and when we see aqueous we assume Kc.
Re: Cyanido
The rule is if it ends in ide it turns to ido
- Sun Dec 08, 2019 11:31 pm
- Forum: Conjugate Acids & Bases
- Topic: Neutralization Equations
- Replies: 3
- Views: 408
Re: Neutralization Equations
neutralization is usually strong acids and bases I think
- Sun Dec 08, 2019 11:28 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: 6B.1
- Replies: 2
- Views: 143
Re: 6B.1
That's the only way to get a number without knowing the concentrations. Since it's -log (0.12H+)-(-log (H+), you can change it to log (H+)-(log 0.12(H+)) and thus you can take log 1/0.12 since the H+ will cancel.
- Sun Dec 08, 2019 11:11 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: common acids and bases
- Replies: 4
- Views: 257
Re: common acids and bases
My TA mentioned that usually the organic molecules were the weak ones.
- Sun Dec 08, 2019 11:09 pm
- Forum: Polyprotic Acids & Bases
- Topic: Amphiprotic vs Amphoteric
- Replies: 6
- Views: 584
Re: Amphiprotic vs Amphoteric
Amphiprotic is always amphoteric but amphoteric is not always amphiprotic.
- Sun Dec 01, 2019 3:31 pm
- Forum: Bronsted Acids & Bases
- Topic: Net Ionic Equations
- Replies: 3
- Views: 271
Re: Net Ionic Equations
It depends on whether or not they dissociate completely in water.
- Sun Dec 01, 2019 3:27 pm
- Forum: Amphoteric Compounds
- Topic: 6A.11
- Replies: 2
- Views: 135
Re: 6A.11
I think the easiest way when you're told that the molecule is amphoteric is to just add a proton and minus a proton. So you would end up with PO4 (3-) and H2PO4 for HPO4.
- Sun Dec 01, 2019 3:22 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: [H3O+] and [OH-]
- Replies: 3
- Views: 252
Re: [H3O+] and [OH-]
If you want to calculate directly [H3O+][OH-]=10^-14.
- Sun Dec 01, 2019 3:19 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acid Strength
- Replies: 3
- Views: 220
Re: Acid Strength
My TA explained it as those molecules having more resonance usually and thus without the proton they are more stable so they are more willing to be dissociated. At least this is how I understood it.
- Sun Dec 01, 2019 3:18 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Strong vs Weak Acids
- Replies: 7
- Views: 508
Re: Strong vs Weak Acids
Usually acids that have an atom which is more electronegative will be stronger
- Sun Nov 24, 2019 4:33 pm
- Forum: Biological Examples
- Topic: Transition metals and their biological importance
- Replies: 2
- Views: 168
Re: Transition metals and their biological importance
I don't think you actually have to memorize them because he probably just wanted to show us the importance of these metals.
Re: #9C3 d
Doesn't it have to do with alphabetical order?
- Sun Nov 24, 2019 4:28 pm
- Forum: Bronsted Acids & Bases
- Topic: Acid Naming
- Replies: 2
- Views: 101
Re: Acid Naming
Yes cation before anion
- Sun Nov 24, 2019 4:27 pm
- Forum: Naming
- Topic: Coordination number
- Replies: 7
- Views: 370
Re: Coordination number
Coordination numbers depend on the number of bonds.
- Sun Nov 24, 2019 4:24 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: transition metals
- Replies: 2
- Views: 119
Re: transition metals
You calculate oxidation numbers based on charges of the rest of the compound.
- Sun Nov 17, 2019 2:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR notation
- Replies: 8
- Views: 510
Re: VSEPR notation
A for the central atom. X for the bonded atoms. E for the lone pairs.
- Sun Nov 17, 2019 2:15 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw
- Replies: 23
- Views: 934
Re: Seesaw
I don't know if the angle has a difference that is significant. 90 and 120 should be fine.
- Sun Nov 17, 2019 11:20 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Shapes We Are Expected to Know
- Replies: 6
- Views: 393
Re: Shapes We Are Expected to Know
He said that the ones we discussed in class in Friday we need to know and we also need to know Monday's lecture.
- Sun Nov 17, 2019 11:19 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Model
- Replies: 5
- Views: 125
Re: VSEPR Model
Electron focuses more on how the electrons are placed and bonding than molecular. So molecular tends to be more general focusing on regions of electron density while electron focuses on lone pairs and where they are placed because of the electron electron repulsion.
- Sun Nov 17, 2019 11:16 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: identifying pi & sigma bonds
- Replies: 3
- Views: 216
Re: identifying pi & sigma bonds
I think he's going to cover this more in depth on Monday
- Sun Nov 10, 2019 5:20 pm
- Forum: Dipole Moments
- Topic: 3F. 5
- Replies: 2
- Views: 85
Re: 3F. 5
H bond needs a hydrogen bonded to a highly electronegative atom such as F, O, and N.
- Sun Nov 10, 2019 5:06 pm
- Forum: Electronegativity
- Topic: Ionization Energy vs. Electronegativity
- Replies: 9
- Views: 9585
Re: Ionization Energy vs. Electronegativity
Think of ionization energy as what it takes to make an anion and electronegativity is how badly it wants to be negative. That's how I remember it. Don't know if that helps
- Sun Nov 10, 2019 5:02 pm
- Forum: Bond Lengths & Energies
- Topic: Interaction Potential Energy Formula
- Replies: 2
- Views: 164
Re: Interaction Potential Energy Formula
You just have to be aware of the proportionality and that r is to the power of 6 so it has a pretty big impact.
- Sun Nov 10, 2019 4:51 pm
- Forum: Bond Lengths & Energies
- Topic: London Forces
- Replies: 6
- Views: 323
Re: London Forces
London forces are created when there are slight e density fluctuations and these are just in all compounds
- Sun Nov 10, 2019 4:42 pm
- Forum: Bond Lengths & Energies
- Topic: Bond strength
- Replies: 4
- Views: 246
Re: Bond strength
It also has to do with size. Larger atoms results in longer bond length and a weaker bond.
- Sun Nov 03, 2019 2:54 pm
- Forum: Dipole Moments
- Topic: Midterm
- Replies: 8
- Views: 318
Re: Midterm
Friday's lecture. The last slide was going to be on it but then we got class canceled on Monday.
- Sun Nov 03, 2019 2:52 pm
- Forum: Resonance Structures
- Topic: Defining Resonance Structures
- Replies: 3
- Views: 135
Re: Defining Resonance Structures
I think that formal charge also comes into play.
- Sun Nov 03, 2019 2:45 pm
- Forum: Octet Exceptions
- Topic: Expanded Valence Shells
- Replies: 2
- Views: 134
Re: Expanded Valence Shells
My TA said that it has to do with energies and hybridizations. An easy way is just to think about it in terms of being able to draw from the d subshells which only start when n=3
- Sun Nov 03, 2019 2:43 pm
- Forum: Octet Exceptions
- Topic: What are radicals
- Replies: 7
- Views: 247
Re: What are radicals
Because they are exceptions to the octet rule, they are highly reactive and unstable. They're very dangerous because they can modify DNA and other biologic molecules. They usually don't remain in that state for long.
- Sun Nov 03, 2019 2:29 pm
- Forum: Ionic & Covalent Bonds
- Topic: Relationship with Polarity
- Replies: 3
- Views: 124
Re: Relationship with Polarity
You can think of bigger polarity as one element wanting and pulling on electrons more. Thus ionic is just when there is such a big difference that one element "gets" the electron instead of sharing it.
- Sun Oct 27, 2019 1:52 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: 2B. 23
- Replies: 2
- Views: 167
Re: 2B. 23
The preferred formal charge is 0. When he gave the example of sulphate SO4, the lewis structure was technically correct but the formal charges weren't ideal. We use formal charge to give us better lewis dot structures. When you're drawing lewis dot structures and you can't get all of the formal char...
- Sun Oct 27, 2019 1:47 pm
- Forum: Lewis Structures
- Topic: Bond Lengths
- Replies: 2
- Views: 85
Re: Bond Lengths
When he was talking about Benzene, he was pointing out that the bonds are neither the length of a single or a double bond because of the resonance. The bond lengths depend based on the elements and what type of bond it is. For example N-O in nitrate was 1.24 A while C-C in benzene was 1.39 A.
- Sun Oct 27, 2019 1:43 pm
- Forum: Ionic & Covalent Bonds
- Topic: P, Cl, and S octet tule exceptions
- Replies: 4
- Views: 259
Re: P, Cl, and S octet tule exceptions
Other elements such as N and O and F can't because they are in N=2 meaning they only have access to s and p and can only form an octet. In general just remember n=3 as what makes it an exception.
- Sun Oct 27, 2019 1:41 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2.A.17
- Replies: 3
- Views: 150
Re: 2.A.17
Positive means that they lost electrons so that's why you subtract from the ground state. If they were negative you would add because they gained electrons.
- Sun Oct 27, 2019 1:39 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2A.15
- Replies: 4
- Views: 174
Re: 2A.15
Losing 1 electron in the p orbital doesn't lead to an octet because there are still 2 electrons in the s orbital
- Sun Oct 20, 2019 11:02 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heinsberg Uncertainty Equation Post-Module Question #18
- Replies: 2
- Views: 140
Re: Heinsberg Uncertainty Equation Post-Module Question #18
The uncertainty of the electron would be diameter and you used radius.
- Sun Oct 20, 2019 10:59 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: 1.B #15
- Replies: 2
- Views: 176
Re: 1.B #15
The part where they say "Model the atom as a one-dimensional box with a length equal to the diameter of the actual atom." just means make delta x = to diameter. That's basically what you always do when you see diameter and uncertainty. Then you get speed by changing delta p into m times de...
- Sun Oct 20, 2019 10:54 am
- Forum: Properties of Electrons
- Topic: Shared Electrons
- Replies: 4
- Views: 248
Re: Shared Electrons
It has to do with electron repulsions. The electrons make sure every orbital has one electron first because two electrons in the orbital has repulsions. At least that's what I remember from high school.
- Sun Oct 20, 2019 10:52 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: p- orbital
- Replies: 3
- Views: 123
Re: p- orbital
Hung Indy Bui 3H is right, it all depends on how you label it and look at it. You can go any way you want.
- Sun Oct 20, 2019 10:37 am
- Forum: *Shrodinger Equation
- Topic: Shrodinger Equation
- Replies: 3
- Views: 118
Re: Shrodinger Equation
Dr. Lavelle said he wouldn't go into the deriving of the equation because that was out of the scope of the class.
- Sat Oct 12, 2019 1:04 pm
- Forum: Properties of Electrons
- Topic: Mass of Electron in De Broglie Equation
- Replies: 4
- Views: 146
Re: Mass of Electron in De Broglie Equation
Even though we didn't need it, I'm pretty sure on the last test Dr. Lavelle printed out the mass of an electron on the formula sheet
- Sat Oct 12, 2019 1:02 pm
- Forum: Properties of Electrons
- Topic: Clarification on particle vs wave properties
- Replies: 3
- Views: 232
Re: Clarification on particle vs wave properties
I think that many things have wavelike properties but they aren't really detectable such as when they are smaller than 10^-15 and then you say they have more particle like properties
- Sat Oct 12, 2019 1:00 pm
- Forum: Properties of Electrons
- Topic: Circular Standing Wave
- Replies: 4
- Views: 206
Re: Circular Standing Wave
Everything is quantized. It's not like a normal equation where you can plug in any number. There are only specific energies.
- Sat Oct 12, 2019 12:58 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Week 2 Homework Problems [ENDORSED]
- Replies: 67
- Views: 7200
Re: Week 2 Homework Problems [ENDORSED]
For week 3, we definitely have to do quantum.
- Sat Oct 12, 2019 12:55 pm
- Forum: Limiting Reactant Calculations
- Topic: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
- Replies: 68
- Views: 6595
Re: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
Showing your work can also make it easier for you to double check your answers too!
- Sat Oct 12, 2019 12:54 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg equation [ENDORSED]
- Replies: 73
- Views: 8680
Re: Rydberg equation [ENDORSED]
The rydberg equation I think is just an equation that combines a few steps of the Einitial - Efinal method.
- Wed Oct 02, 2019 10:46 pm
- Forum: Empirical & Molecular Formulas
- Topic: Empirical and Molecular Formula Masses
- Replies: 5
- Views: 248
Re: Empirical and Molecular Formula Masses
Empirical formula is the lowest ratio so molecular formula should not be greater than the empirical.
- Wed Oct 02, 2019 10:39 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Molar Mass
- Replies: 10
- Views: 1042
Re: Molar Mass
For some problems where you have to find the molar mass of a sample with a lot of isotopes just multiply the isotope percentage by the isotope weight and add all of them together.
- Wed Oct 02, 2019 10:34 pm
- Forum: Balancing Chemical Reactions
- Topic: Combustion Reaction Notation
- Replies: 6
- Views: 184
Re: Combustion Reaction Notation
One thing we talked about today in discussion is that when you see oxidized that also means that it is combustion. Thought that would be useful in decoding problems.
- Wed Oct 02, 2019 10:31 pm
- Forum: Limiting Reactant Calculations
- Topic: limiting reactant
- Replies: 5
- Views: 353
Re: limiting reactant
One thing that stuck with me throughout high school chemistry is the mole tunnel. If you're having trouble just always remember grams to moles to moles to grams.
- Wed Oct 02, 2019 10:29 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student - Part II [ENDORSED]
- Replies: 298
- Views: 245051
Re: Advice from a Medical Student - Part II [ENDORSED]
Thanks so much for taking the time to help out all of us who are so clueless. You gave such great and meaningful advice.